package com.an;

public class HomeWork_9 {
    public static void main(String[] args) {
        int []arr={1,1,2,2,5,5,7,4,4,9,9};
        int dest=0;
        for (int i = 0; i <arr.length ; i++) {
         dest^=arr[i];
        }
        System.out.println(dest);
    }
}
